Correlations in quantum gravity and cosmology
Open Access
- Author:
- Baytas, Bekir
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- May 18, 2018
- Committee Members:
- Sarah Elizabeth Shandera, Dissertation Advisor/Co-Advisor
Sarah Elizabeth Shandera, Committee Chair/Co-Chair
Eugenio Bianchi, Committee Member
Martin Bojowald, Committee Member
Donghui Jeong, Outside Member - Keywords:
- loop quantum gravity
cosmology
quantum gravity - Abstract:
- We study what kind of implications and inferences one can deduce by studying correlations which are realized in various physical systems. In particular, this thesis focuses on specific correlations in systems that are considered in quantum gravity (loop quantum gravity) and cosmology. In loop quantum gravity, a spin-network basis state, nodes of the graph describe un-entangled quantum regions of space, quantum polyhedra. We introduce Bell-network states and study correlations of quantum polyhedra in a dipole, a pentagram and a generic graph. We find that vector geometries, structures with neighboring polyhedra having adjacent faces glued back-to-back, arise from Bell-network states. The results present show clearly the role that entanglement plays in the gluing of neighboring quantum regions of space. We introduce a discrete quantum spin system in which canonical effective methods for background independent theories of quantum gravity can be tested with promising results. In particular, features of interacting dynamics are analyzed with an emphasis on homogeneous configurations and the dynamical building-up and stability of long-range correlations. We conclude that an analysis of the building-up of long-range correlations in discrete systems requires non-perturbative solutions of the dynamical equations. For the early universe cosmology part of the thesis, we present examples of non-Gaussian statistics that can induce bispectra matching local and non-local (including equilateral) templates in biased sub-volumes. We find cases where the biasing from coupling to long wavelength modes affects only the power spectrum, only the bispectrum or both.